Cast-in-place combination aperture closures and pipe seals for use with on-site waste disposal systems, such as in a septic system having a poured concrete septic tank or fluid distribution box are known in the art. A septic tank or fluid distribution box normally has sidewalls defining pipe-receiving apertures for the receipt of inlet or outlet pipes. The combination aperture closure member and pipe seals, which are elastomeric, are positioned in the pipe-receiving apertures and cast in the concrete sidewalls surrounding the pipe-receiving apertures. The combination closure member and pipe seals are then used either to close the pipe-receiving apertures or are opened to provide a watertight seal for a pipe.
During assembly of a septic system it is sometimes preferable to insert a pipe from the inside of a septic tank or distribution box out, as opposed from the outside in. This "inside out" insertion is preferable, for example, when a septic tank is positioned very close to a distribution box. In addition, it is preferable to secure the pipe seal to the pipe with a clamp ring to ensure a strong and a watertight connection.
U.S. Pat. No. 4,732,397 to Gavin discloses an elastomeric seal and closure member including a cylindrical body portion and an integral frusto-conical skirt therein. The skirt has a knockout web at a smaller diameter end that can be removed to allow the frusto-conical skirt to receive the end of a pipe. The disclosed seal and closure member, however, only allows a pipe to be inserted into the fluid distribution box from outside the box. In addition, the frusto-conical skirt frictionally engages the pipe but is not adapted to receive a clamp for clamping the skirt to the pipe.
Gavin also discloses a mandrel for holding the seal and closure member in a form or mold during pouring of the concrete fluid distribution box. The mandrel is bolted to the form and has frusto-conical sidewall that tightly fits within the frusto-conical skirt of the seal and closure member to hold the seal and closure member in place until the concrete of the box is set and the mandrel and the form removed.
U.S. Pat. No. 4,951,914 to Meyers et al. discloses a pipe seal assembly including a seal member and a mandrel. The seal member includes a main cylindrical wall member and an integral frusto-conical flange member for receiving a pipe. The main cylindrical wall member releasably retains a knockout plug. The mandrel includes a frusto-conical sidewall having an undercut portion at a smaller diameter end thereof for tightly receiving and holding the frusto-conical flange member of the seal member. The disclosed seal member of Meyers et al., however, only allows a pipe to be inserted into the fluid distribution box from outside the box. In addition, the frusto-conical flange member frictionally engages the pipe but is not adapted to receive a clamp for clamping the flange member to the pipe.
What is desired, therefore, is a combination closure and pipe seal that allows a pipe to be inserted through the pipe seal from inside the container as well as from outside the container. The combination closure and pipe seal should also accommodate a clamp ring for clamping the pipe seal to the pipe to ensure a strong and watertight connection. In addition, a mandrel for securing the combination closure and pipe seal in a form or mold before and during pouring of a concrete container incorporating the combination closure and pipe seal is also desired.